Kicked off xbox

Sounds like a denial of service attack.

To get back online you need a new IP address.

With most ISP's you should be able to get a new IP address by simply disconnecting the power to your modem/router for a few minutes.

If that doesn't work you would need to contact your ISP and tell them you may be a victim of a ddos attack and they should then be able to change your IP address.

If possible call up the games from your file share (I think MW3 temp saves them) and have a look through for any sudden disconnections after killing a certain player. If you can't find any then I'm inclined to think it's a problem at your end rather than
a hack.

Could be worth posting in the MW3 forum on here -
http://forums.xbox.com/xbox_forums/xbox_360_games/a_d/call_of_duty_modern_warfare_3/f/2315.aspx - and IW forums to see if anyone else has encountered this.

No, have noo ideal. Thanks anyway for replying. Have a good one

Can't find anything about such a hack on the dodgy sites and I'd be intrigued to know how they're managing to send such a command to another person's console. Apart from your friend did you notice any other sudden disconnections from players who'd killed
the person you and your friend did?

I would first go and file a compliant against him on xbox live, that way he can be dealt with, we can only offer support here nothing more. I would then recommend you go
here and chat with Microsoft Support which can help you to connect online if he did have something to do with it.